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In the flow of ultrasound

Sponsored content | donderdag 20 mei 2021

To make the right decision, you need to understand the matter. In flow this is just so. We’re happy to share with you how the inline ultrasonic flowmeter works and why an ultrasonic flowmeter tells you more than just flowrate. In case of Flowmax, this applies equally to the industrial and the aseptic Single Use instruments.

Let’s start with the basics.

All flowmeters use physics to measure a flowrate, such as Faraday’s law for conductive liquids and the Coriolis-effect to measure mass flow. Ultrasonic instruments use the speed of sound as a primary reference to measure the speed of a liquid inside the flowtube.
It is a fact that sound travels through a liquid at a specific speed. When the liquid flows, sound travels faster with -and slower against- the flowdirection.  We use this time-difference to calculate the flowspeed which is proportional to the volume-flow.
In practice, Flowmax calculates 250 flowmeasurements each second and converts these into a  smooth 4-20 mA signal or pulse-output.

Required liquid-property

Flowmax requires only one liquid-property to work.
Conductivity, PH or turbidity don’t play a role, as long as the liquid conducts the acoustic signal.
There are exceptions where the acoustic signal can be absorbed by the liquid. This might be the case in high-concentrate NaOH-solution.

Nothing beats in-line!

The major and generic benefit of an in-line instrument is the guaranteed accuracy, enabled by the individual calibration data which are stored in the instrument.

Functional advantages

In addition to the actual flowrate, the ultrasonic measuring principle and internal processor provide a range of functionalities, we mention the top-three.
Flowmax will notice any gas-bubbles in the liquid and give a warning.
The ultrasonic measuring principle works two-way, making sure reverse-flow is detected and measured.
Monitoring the speed of sound will indicate -unwanted- changes in the liquid.

Three differences between Industrial and Single Use

So far we’ve seen common technology, standardized working principles and generic functions, now it’s time to highlight differences which make the Single Use “fit for purpose”.
First concern is using approved and certified PolyProplylene (PP) material which can safely be used in your SU assembly.
Next priority is cleanliness. Immediately after calibration, the instruments go to a cleanroom to be washed, dried and double-bag-packed in nitrogen atmosphere.
As a final measure, gamma-radiation is commonly applied.
The third aspect is cost-driven. The design is modified to have separate electronics, this saves money since only the wetted part needs to be disposed, the electronics are permanent.

One final thought……

Although the term ‘Single Use’ seems to indicate a short life-span, life-time is not a difference with Industrial instruments.
We.Deliver.Trust in standard or Single Use application, that’s how we flow 😉.